From the Java virtual machine's perspective, arrays and enumerated types (or enums) are just classes. Many of the methods in Class may be used on them. Reflection provides a few specific APIs for arrays and enums. This lesson uses a series of code samples to describe how to distinguish each of these objects from other classes and operate on them. Various errors are also be examined.

Arrays

Arrays have a component type and a length (which is not part of the type). Arrays may be maniuplated either in their entirety or component by component. Reflection provides the java.lang.reflect.Array class for the latter purpose.

• Identifying Array Types describes how to determine if a class member is a field of array type
• Creating New Arrays illustrates how to create new instances of arrays with simple and complex component types
• Getting and Setting Arrays and Their Components shows how to access fields of type array and individually access array elements
• Troubleshooting covers common errors and programming misconceptions

Enumerated Types

Enums are treated very much like ordinary classes in reflection code. Class.isEnum() tells whether a Class represents and enum. Class.getEnumConstants() retrieves the enum constants defined in an enum. java.lang.reflect.Field.isEnumConstant() indicates whether a field is an enumerated type.

• Examining Enums illustrates how to retrieve an enum's constants and any other fields, constructors, and methods
• Getting and Setting Fields with Enum Types shows how to set and get fields with an enum constant value
• Troubleshooting describes common errors associated with enums